RE: Satellite ranging

Can you do this on voice repeaters ?
-----------------------------------------
Andrew Rich - VK4TEC
Satellite Ground Station for PCSAT2
vk4tec@tech-software.net
www.tech-software.net
Brisbane AUSTRALIA
-----Original Message-----
From: owner-AMSAT-BB@AMSAT.Org [mailto:owner-AMSAT-BB@AMSAT.Org]On
Behalf Of g3ruh R Miller
Sent: Monday, 10 October 2005 5:04 AM
To: amsat-bb@AMSAT.Org
Subject: Re: [amsat-bb] Satellite ranging
On 2005 Oct 09 Andrew Rich wrote:
> Has anyone done ranging experients, using a two channel CRO and sending a
> signal via a satelite and working out
> the slant range from delay ?
Satellite Ranging
-----------------
Yes. All Amsat P3 satellites had/have ranging capabilities. Either the
flight
computer could regenerate and return a 400 bps signal, or a transponder
could return anything. The resultant range measurements were used to
determine the satellite's orbit, and will do so again for P3E.
When AO-40 was working you could send pulses through the transponder, and
watch the changing delay. Pulse-at-a-time measurements are of course noisy,
and you can do far better by sending a rapid stream of pulses. These can be
faster that the round-trip time allows if you make the pulses a unique
stream
of +pulses and -pulses, which manifests itself as a quasi-random data
stream.
With this you can, with suitable mix of hardware and software, get both
uplink pulses and downlink pulses "into" a computer and do all the time to
range range conversion automatically to remarkable accuracy (sub km).
An article about this is at:
http://www.amsat.org/amsat/articles/g3ruh/123.html
Hope useful.
73 de James G3RUH - (AO-10), AO-13 and AO-40 command station
--
==========================================================================
James R Miller WWW/PGP: http://www.jrmiller.demon.co.uk/
Cambridge, England Stardate: 2005 Oct 09 [Sun] 1902 utc
==========================================================================
----
Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
----
Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org